seq_file: reuse string_escape_str()

strint_escape_str() escapes input string by given criteria.  In case of
seq_escape() the criteria is to convert some characters to their octal
representation.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/seq_file.c

@@ -13,6 +13,7 @@
 #include <linux/cred.h>
 #include <linux/mm.h>
 #include <linux/printk.h>
+#include <linux/string_helpers.h>
 
 #include <asm/uaccess.h>
 #include <asm/page.h>
@@ -377,26 +378,12 @@ EXPORT_SYMBOL(seq_release);
  */
 void seq_escape(struct seq_file *m, const char *s, const char *esc)
 {
-	char *end = m->buf + m->size;
-	char *p;
-	char c;
+	char *buf;
+	size_t size = seq_get_buf(m, &buf);
+	int ret;
 
-	for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) {
-		if (!strchr(esc, c)) {
-			*p++ = c;
-			continue;
-		}
-		if (p + 3 < end) {
-			*p++ = '\\';
-			*p++ = '0' + ((c & 0300) >> 6);
-			*p++ = '0' + ((c & 070) >> 3);
-			*p++ = '0' + (c & 07);
-			continue;
-		}
-		seq_set_overflow(m);
-		return;
-	}
-	m->count = p - m->buf;
+	ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc);
+	seq_commit(m, ret < size ? ret : -1);
 }
 EXPORT_SYMBOL(seq_escape);